Second 'Catug' Unit For Hvide Shipping Christened At Galveston

The second in the series of unique rigid connecting tug-barge combinations built in Galveston, Texas, was christened in December. The M/V Seabulk Magnachem, and its barge SCC 3902, were built for Hvide Shipping of Ft. Lauderdale, Fla., which will operate the vessel for Diamond Shamrock Chemical Corporation on the Gulf and East Coasts. The christening ceremonies took place at the Galveston Wharves Pier 39, with The Diamond Shamrock Group vice president's wife, Mrs. Roger Batchelor, acting as the sponsor for the M/V Seabulk Magnachem, and Mrs. William Bricker, wife of the Diamond Shamrock president, sponsoring the barge SCC 3902.

The ITB was constructed by Galveston Shipbuilding Company, Inc. under contract to Kelso Shipbuilding which was acquired by GSC this year. Kelso Shipbuilding was formerly owned by the C. Brewer Company, Ltd. of Honolulu, which was the parent company when the two ITB construction agreements with Hvide were made. The first of the ITBs, called "Catugs," was delivered in 1974 to Seabulk Corporation, which is a subsidiary of Hvide Shipping, Incorporated. Christened the Seabulk Challenger, the tug and its matching 41,800- dwt tank barge STL 3901 was designed by J.B. Hargrave Naval Architects, Inc. of West Palm Beach, Fla., in collaboration with Seabulk.

The most recent Catug, Seabulk Magnachem, was launched in July of last year and is powered by two 7,000-bhp Colt- Pielstick PC-2 14-cylinder, directreversing diesels located in separate engine rooms in the two catamaran hulls. Each engine drives a 17-foot-diameter fourbladed Lipps propeller with 18.7- inch pitch. The propellers are driven through a 5.29:1 Lufkin reduction gear. Pneumatically operated clutches and brakes allow automatically sequenced engine starts and idling in either direction without the propeller shaft turning.

Controlled pneumatically from the bridge, the KaMeWa 80/3S/ FP bow thruster is driven through a right-angle drive and reversing gear. Power is provided by a Caterpillar D-349 diesel engine rated at 1,000 bhp.

The Seabulk Magnachem will be matched with barge SCC 3902 to be completed in the near future. The SCC 3902 differs from the first such barge in that it is double-skinned compartmentalized for both caustic and noncaustic cargo. The 42,000-dwt barge, and its power unit Catug, feature hull lines which are faired for lowest water resistance when the vessels are joined.

The first in the Catug series, the Seabulk Challenger and STL 3901, have been approved for full, unrestricted ocean service by the U.S. Coast Guard, American Bureau of Shipping, and the Maritime Administration. The Coast Guard has approved a manning scale of 15 for the Catug. Better propulsive efficiency is one of the advantages Seabulk claims due to the twin-hull con- for lowest water resistance when the vessels are joined.

The first in the Catug series, the Seabulk Challenger and STL 3901, have been approved for full, unrestricted ocean service by the U.S. Coast Guard, American Bureau of Shipping, and the Maritime Administration. The Coast Guard has approved a manning scale of 15 for the Catug. Better propulsive efficiency is one of the advantages Seabulk claims due to the twin-hull con- NAME COMPANY CITY TYPE OF VESSEL(S).

figuration of the tugs. The design accommodates large, slow-turning propellers that are spaced widely apart. The arrangement virtually eliminates propeller cavitation and the resulting vibration. Maneuverability improvements are provided by this propeller spacing and bow thruster.

The design of the catamaran provides close similarities in roll period, centers of gravity and buoyancy to the barge. The reduced stress at the connections allows elimination of the costly high-strength steel normally required at these points.

The "unmanned tank barge" loadline increases carrying capacity approximately 17 percent over ships of the same molded depth.

The tug and barge measure 121 feet and 589 feet long, respectively ; when locked together, their combined length is 630 feet overall.

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